The present disclosure relates to toners suitable for electrophotographic apparatuses.
Numerous processes are within the purview of those skilled in the art for the preparation of toners. Emulsion aggregation (EA) is one such method. These toners may be formed by aggregating a colorant with a latex polymer formed by emulsion polymerization. For example, U.S. Pat. No. 5,853,943, the disclosure of which is hereby incorporated by reference in its entirety, is directed to a semi-continuous emulsion polymerization process for preparing a latex by first forming a seed polymer. Other examples of emulsion/aggregation/coalescing processes for the preparation of toners are illustrated in U.S. Pat. Nos. 5,403,693, 5,418,108, 5,364.729, and 5,346,797, the disclosures of each of which are hereby incorporated by reference in their entirety. Other processes are disclosed in U.S. Pat. Nos. 5,527,658, 5,585,215, 5,650,255, 5,650,256 and 5,501,935, the disclosures of each of which are hereby incorporated by reference in their entirety.
Polyester EA ultra low melt (ULM) toners have been prepared utilizing amorphous and crystalline polyester resins. Some of these toners have poor charging characteristics, which may be due to the crystalline resin component migrating to the surface during coalescence. The amorphous resin may also be plasticized by the crystalline resin, which may result in poor blocking. A core-shell approach, wherein a shell including a linear amorphous resin may be added to encapsulate the crystalline-amorphous composite has been attempted; however, charging and blocking still needs to be improved.